In your 1997 Ford F-150, a P0306 is a diagnostic trouble code indicating a misfire in cylinder No. 6. Check the spark plug and plug wire, fuel injector and ignition coil on cylinder No. 6. Try swapping components with those on another cylinder to see if the code changes.
This and other misfire DTCs can be set if you run out of gas. Other causes can be, but are not limited to, lack of fuel pressure or compression, intake air leaks creating loss of vacuum, a faulty oxygen sensor or loss of pressure in the evaporative emission system. If other DTCs are present, the P0306 may be a secondary code caused by a malfunction in another system, meaning the P0306 may be a result and not the primary cause of the problem with your F-150. Consider all codes present in memory when diagnosing DTCs.
